When I lived in the South of France (1996-98) there was a very good athlete (aged about 22) who ran for the local club 'Cagnes sur Mer' - his name was William Struyven....he had been running road races since age 11, as he was coached by his father, also a runner.
During the 1996-1998 time, Struyven (A Frenchman of flemish origin, hence the name) ran 29:00 10.000 at the French track championships (placing around 5th in the race, and first non Arab). He also ran around 63 minutes in the Nice Half Marathon, and was the first 'white runner' behind a bunch of Kenyans.
The interesting thing about all of this is that Struyven was at the time (and still is) a minimalist in training, usually running around 50-60 kilometers a week (30-37 miles a week). He was coached by Pascal Drewitz (3:43/1500, and 8:37/3000 sc, and 2:20 marathon)....and his quality sessions were things like a bunch of 300's or 200's on the track, or repeat 2km runs on the track.....but I saw most of these sessions and they were not that impressive, because William lacks basic speed, having trouble to even go under 59 seconds for 400m flat out!
But such is his strength (Struyven) and his ability to run close to his maximum, that he has been able to run 29:00-30:00 for 10km for years and years, and still does.
He made an attempt at the marathon in Paris a few years ago, and slightly upped his mileage to about 10km per day (6 miles a day) with a long run (1.5 hours) on Sundays, but after going through half way in around 66 minutes, blew up and finished in 2:24....saying the marathon was not for him.
William does not like doing mileage, but most of his runs are tempo runs, and good luck if you try to follow him, because he starts steady (around 4.00 per km) but often finishes his runs at around 3:00 per km....he is just an animal on those 30 minute runs....tempo, tempo, tempo.
The last few years have not seem him do much track, he runs the road circuit in the South of France for money, and sadly this has resulted in him staying at a lower level than he should.
He could have been like Brian Sell, but this would have necessitated a lot of mileage which William does not like.
But certainly, I have rarely seen an athlete as talented as William. One time he was 'forced' to run the 1500 at the "Interclubs" in Nice....and of course he was dead last on the first lap, way off the pace, but then as the others got tired, William started getting faster and faster, and he finished the race in 3:56...a p.b. and not bad for a guy who had trouble running sub. 30 seconds for his track sessions of 200m